Validate if all layers dependencies exist

internal/layerfile/layerfile.go

@@ -12,7 +12,10 @@ import (
 	"github.com/ergomake/layerform/pkg/data"
 )
 
-var ErrInvalidDefinitionName = errors.New("invalid layer definition name")
+var (
+	ErrInvalidDefinitionName  = errors.New("invalid layer definition name")
+	ErrDependencyDoesNotExist = errors.New("dependency does not exist")
+)
 
 var alphanumericRegex = regexp.MustCompile("^[A-Za-z0-9][A-Za-z0-9_-]*[A-Za-z0-9]$")
 
@@ -40,6 +43,10 @@ func FromFile(sourceFilepath string) (*layerfile, error) {
 }
 
 func (lf *layerfile) ToLayers() ([]*data.LayerDefinition, error) {
+	if err := lf.validateLayersDependencies(); err != nil {
+		return nil, errors.Wrap(err, "fail to validate layers dependencies")
+	}
+
 	dir := path.Dir(lf.sourceFilepath)
 
 	dataLayers := make([]*data.LayerDefinition, len(lf.Layers))
@@ -89,3 +96,21 @@ func (lf *layerfile) ToLayers() ([]*data.LayerDefinition, error) {
 
 	return dataLayers, nil
 }
+
+func (lf *layerfile) validateLayersDependencies() error {
+	names := make(map[string]struct{})
+
+	for _, l := range lf.Layers {
+		names[l.Name] = struct{}{}
+	}
+
+	for _, l := range lf.Layers {
+		for _, d := range l.Dependencies {
+			if _, ok := names[d]; !ok {
+				return errors.Wrap(ErrDependencyDoesNotExist, d)
+			}
+		}
+	}
+
+	return nil
+}

internal/layerfile/layerfile_test.go

@@ -135,3 +135,71 @@ func TestToLayers_ValidateNameOfLayerDefinitions(t *testing.T) {
 		})
 	}
 }
+
+func TestToLayers_ValidateAllDependenciesExist(t *testing.T) {
+	tests := []struct {
+		name string
+		lf   layerfile
+		err  error
+	}{
+		{
+			name: "Dependencies don't exist",
+			lf: layerfile{
+				Layers: []layerfileLayer{
+					{
+						Name:         "foo",
+						Dependencies: []string{"bar", "baz"},
+					},
+					{
+						Name: "bar",
+					},
+				},
+			},
+			err: ErrDependencyDoesNotExist,
+		},
+		{
+			name: "Dependencies exist",
+			lf: layerfile{
+				Layers: []layerfileLayer{
+					{
+						Name:         "foo",
+						Dependencies: []string{"bar"},
+					},
+					{
+						Name: "bar",
+					},
+				},
+			},
+		},
+		{
+			name: "Layers have no dependencies",
+			lf: layerfile{
+				Layers: []layerfileLayer{
+					{
+						Name: "foo",
+					},
+					{
+						Name: "bar",
+					},
+				},
+			},
+		},
+		{
+			name: "No layers",
+			lf: layerfile{
+				Layers: []layerfileLayer{},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := tt.lf.ToLayers()
+			if tt.err == nil {
+				assert.NoError(t, err)
+			} else {
+				assert.ErrorIs(t, err, tt.err)
+			}
+		})
+	}
+}